The primary goal of this project is to determine the mechanisms determining the levels and composition of the plasma lipoproteins in man and in experimental animals. Animal models of experimental hyperlipidemia will be developed in rats. Hyperlipemia will be induced by feeding diets high in sucrose or diets containing added cholesterol. In addition, hyperlipemia will be induced of diabetes, the nephrotic syndrome, hypothyroidism, and biliary obstruction. The effects of various dietary modification on the hyperlipidemia will be observed. In addition, hyperlipidemia in man, secondary to diabetes and to the nephrotic syndrome will be studied. In these studied, levels of the various plasma lipoproteins will be measured, as well as their apoprotein composition and distribution. In addition, studies designed to determine the mechanisms responsible for these abnormalities will be performed. BIBLIOGRAPHIC REFERENCES: Bar-On, H., Roheim, P.S., Eder, H.A. Hyperlipoproteinemia in Streptozotocin-Treated Rats. Diabetes 25:509-519, 1976. Swaney, J.B., Braithwaite, F., and Eder, H.A. Characterization of the Apolipoproteins of Rat Plasma Lipoproteins. Biochemistry 16:271, 1977.